/*
 * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
 *
 * This file is part of MjSip (http://www.mjsip.org)
 *
 * MjSip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MjSip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MjSip; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author(s):
 * Luca Veltri (luca.veltri@unipr.it)
 */

package org.zoolu.tools;



/** Generic hash/message-digest algorithm.
 */
public abstract class MessageDigest
{
    /** MessageDigest block update operation.
     * Continues a message-digest operation,
     * processing another message block, and updating the context. */
    abstract public MessageDigest update(byte[] buffer, int offset, int len);


    /** MessageDigest block update operation.
     * Continues a message-digest operation,
     * processing another message block, and updating the context. */
    public MessageDigest update(String str)
    {  byte[] buf=str.getBytes();
        return update(buf,0,buf.length);
    }


    /** MessageDigest block update operation.
     * Continues a message-digest operation,
     * processing another message block, and updating the context. */
    public MessageDigest update(byte[] buffer)
    {  return update(buffer,0,buffer.length);
    }


    /** MessageDigest finalization. Ends a message-digest operation, writing the
     * the message digest and zeroizing the context. */
    abstract public byte[] doFinal();


    /** Gets the MessageDigest. The same as doFinal(). */
    public byte[] getDigest()
    {  return doFinal();
    }


    /** Gets the Message Digest as string of hex values. */
    public String asHex()
    {   return BinTools.asHex(doFinal());
    }

}
